Researchers at the University of Buffalo and the University of California in the United States wanted to apply these previous findings to a larger scale to see if these chemicals promote other forms of nice behaviour, such as giving money to charity.

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The "nice" hormones work by binding people's cells through receptors. Certain genes determine how receptive people are to these hormones.

As part of the study, participants were asked questions about their attitudes toward civic duty, such as whether people have a moral duty to report a crime, other people and whether the world is generally a good or bad place, and about their charitable activities, like giving blood or going to PTA meetings.

Of those surveyed, 711 people provided a sample of saliva for DNA analysis, that showed what form they had of the oxytocin and vasopressin receptors.

Results, published in the journal Psychological Science, showed people have "nice" versions of the genes, which when combined with the subjects' views on the world, make them more likely to help others.

Professor Michel Poulin, of the University of Buffalo, said: "The study found that these genes combined with people's perceptions of the world as a more or less threatening place to predict generosity.

"Specifically, study participants who found the world threatening were less likely to help others - unless they had versions of the receptor genes that are generally associated with niceness.

"These 'nicer' versions of the genes allow you to overcome feelings of the world being threatening and help other people in spite of those fears.

"The fact that the genes predicted behaviour only in combination with people's experiences and feelings about the world isn't surprising because most connections between DNA and social behavior are complex.

"So if one of your neighbours seems really generous, caring, civic-minded kind of person, while another seems more selfish, tight-fisted and not as interested in pitching in, their DNA may help explain why one of them is nicer than the other.

"We aren't saying we've found the niceness gene, but we have found a gene that makes a contribution. What I find so interesting is the fact that it only makes a contribution in the presence of certain feelings people have about the world around them."